Bacteriological oven or incubator.



y affma@ H. L. LOWE.

BAGTERIOLOGIGAL OVEN OR INGUBATOR.

APPLICATION FILED 111111.22, 190e.

997,070. 1 Patented .1u1y 4, 1911.

2 SHEETS-SHEET 1.

WITN ESSES INVENTOR 1 u. L. LOWE. BACTERIOLOGIGAL OVEN '0R INGUBATOR.

*APPLICATION FILED AUG. Z2, 1908.

Patented July 4, 1911.

2 SHEETS*SHEET 2.

INVENTOR Y dwf/(QM,

A wlTNEssEs 1,1/26" HENRY LELAND LOWE, 0F PITTSBURG, PENNSYLVANIA, ASSIGNOR TO SCIENTIFIC.

MATERIALS COMPANY, OF PITTSBURG, PENNSYLVANIA.

BACTER-IOLOGICAL OVEN 0R INCUBATOR.

Specification of Letters Patent.

Patented July 4, 1911.

Application led August .22, 1908. Serial No. 449,867.

To all whom it may concern:

Be it known that I, HENRY LELAND LOWE.l a resident of Pittsburg, in the county of Allegheny and State of Pennsylvania, have invented al new and useful Improvement in Bacteriological Ovens or Incubatore; and I do hereby declare the following to be a full, clear,`and exact description thereof.

My invention relates to ovens or incubators and has special reference to such devices for use in bacteriological purposes.

The objectof lny invention is to provide a cheap, simple and eiicient apparatus of this character which shall be inexpensively heated by such means and in such manner that the temperature will be automatically regulated and maintained substantially uniformA throughout any desired period of operation.

My invention consists, generally stated, in the novel arrangement, construction and combination of parts, as hereinafter more speciically set forth and described and partlcularly pointed out in the claims.

To enable others skilled in the art to which my invention appertains to construct and use my improved oven or incubator, I will describe the same more fully, referring to the accompanying drawing, in which- Figure 1 is a longitudinal sectional view, partly in full lines, of an apparatus constructed in accordance with my invention. Fig. 2 is a cross-section on the line 22 Fig. 1, andv looking in the direction of the arrow. Fig. 3 is a sectional detail view of the contact device. Fig. 4 is a diagram view of the electric circuits employed in the heating and regulating apparatus. Fig. 5 is an enlarged -diagram view of the circuits and showing in full lines the starting position. Fig. 6 is a like view of the circuits and showingmin full. lines the running position. Fig. 7 is a like view showing in full lines the circuits in use when the thermostatic contact is closed.

Like symbols of reference herein indicate like parts in each of the figures of the drawgAs illustrated in Fig. 1, the oven, which may be of any suitable form and'have any desired structural characteristics, is indicatedA as comprising a chamber 1, having a' plurality of shelves 2 therein, and a chamber 3, having suitable heaters located therein, 'such as a plurality of incandescent lamps 4 of equal candle power and of a size to suit conditions, and a like lamp 4 of eight candle power or smaller for acting as a resistance to protect the Contact thermometer and relay hereinafter described. The chamber 1 is here shown as having sheet metal walls 5 and as surrounded by a shell 6, between which and said walls 5 is a chamber filled with liquid 7. Surrounding the shell. 6 is an outer shell 8, and between which and said shell 6 is an air-space 9, and the air in said space on account of its poor conductivity of heat will serve to aid in maintaining a constant temperature in the chamber 1.

The structure above described is mounted upon a base portion 10 which forms a compartment 11 having an ordinary telegraph relay 12 mounted therein for forming a circuit making and breaking device, and an or dinary knife switch 13 of the double pole and double throw character is mounted on the outer surface of the said base portion.

Connected to and extending through the top of the oven is a thermostat 14 which is provided with a bulb 15 and capillary tube or stem 16 connected together, with the bulb projecting downward into the liquid 7 between the shells 5 and 6 to a point therein as may be desirable, and the stem extending somewhat above the top of the oven. A side tube 17 extends out from the stem 16 and above` the topof the oven, which is provided with a nut 18 at its end for the reception and engagement of a displacement screw 19 passing throu'gh a stufiing box 20 on the outer end of said nut and provided with a handle 21 at its free outer end for operating the same. The bulb 15 and stem 16 are filled with mercury which extends into the side tube 17 and above' the same in the stem 16 and a contact wire 22 of steel or platinum is inserted into *the bore of said steml from above the same through its upper open end, and is clamped in a bearing 22 on a stand* ard 23 extending up from the top of the oven. In case the wire 22 inserted into the bore of the tube 16 is used to make the Contact, a rough adjustment of the `temperature of contact may be made by sliding said wire in said tube, and a fine adjustment can be made by the displacement screw 19 in the side tube 17.

A thermometer 24 of the ordinary approved character passes through the top of the oven and enters into the same above the upper shelf 2 therein to, determine the temperature of the oven and the graduated portion 25 extends above the top of the oven for the reading of the saine.

The operation of the circuits is as follows z-*For starting the apparatus with the and d the current being divided at points- 30 and 30 as shown. The circuit is complete through lamps a and b by wire 31 to terminal 31 of switch while the circuit of lamps c and l passes by wire 32 to 32 to contact 32H of the switch all to wire 26".

When switch is thrown over to the full line position as shown in Fig. 4 and Fig. 6, which is the normal running position, the current from main wire 26 passes through wire 32 and dividing, by wires 32 and 32a to lamps (l and 0 respectively and returning by wire 33 to contact 33', special contact 34, wire 35, Contact 36 and wire 37 to switch Contact 38 and thence through switch to main wire 26".

Lamps a and b while in a normally closed circuit couldreceive no appreciable amount of current as they could only be energized by current which has passed through lamps c and (l which lamps have a direct return circuit of practically no resistance through the line 33.

When the heat in liquid 7 reaches a certain predetermined 4point the contact is closed at 14, as shown infull lines in Fig. 7, by reason of contact between the rising mercury and terminal 16 as previously described, at which time the'circuit over wire 35 to contact 36 and wire 37 will be broken by reason of the energizing of magnet 12 through the following circuit; from switch by wires 32, 32:L and 32, lamp 4, magnet 12, mercurial contact 14, wire 35a and 35, special contact 34, wire 33, lamp b and wire 31 to switch. The energizing of magnet 12 breaks the contact between 36 and wire 37 and the lamps will be thrown in series by pairs as follows: From switch by wire 32 through lamps d, and and wire 31 `to switch terminal. Another circuit from switch passes over wires 32, 32a, lamps c and a and wire 31 to switch. The circuits remain with lamps d and Z) in series and lamps c and a in series, and magnet 12 interposed in series with lamps 4 and b through special contact 34, until the temperature of liquid ,7 is sufficiently reduced to lower mercury and break contact 14, at which time arm 36 is released and the circuits are restored to the condition above described and illustrated in Fig. 6.

A condenser, such as is shown at e in Fig. 4 is connected around the mercury contact of the thermometer 14 and mounted beneath the relay 12 for protection, anda special contact, such as is shown at 34 in Fig. 4, is provided on the switch 13 and is interposed in the circuit of the relay 12, so that when said switch is thrown to the left, as shown in dotted lines in said ligure and all the lamps a b c and d are being operated at full current, as at the start, this contact will be broken and thus throw said relay perature may bevmaintained by regulating the number of lamps employed and by adjusting the thermostatic device, so that it will act in accordance with the degree of heat desired.

The parts of the oven or incubator are few and generally of commercial character, with the exception of the contact thermometer, and they are so arranged and used as to enable the practically instant use of the apparatus inits entirety. The device is compact in form and when set up for shipment, will be practically complete.

Other suitable arrangements of the circuit and controlling devices may be employed if desired, as well as others of resistance devices, while Various changes in the design, construction and operation of the apparatus may be resorted to, without departing from the spirit of the invention or sacrificing any of its advantages.

What I claim as my invention, and desire to secure bv Letters Patent, is-

1. In an incubator or bacteriological oven, the combination of' a chamber having a water jacket, a heating chamber located outside of the water jacket, an electrical heating resistance in said heating chamber, a circuit for said heating resistancea second circuit including a make-and-break device, a thermostat extending into said water jacket and adapted to automatically close the makeand-break circuit, and a resistance device also located in said heating chamber and adapted to be automatically thrown into circuit with the first named resistance when said make-and-break circuit is closed by said thermostat.

2. In an incubator or bacteriological oven, the combination of a chamber having a water jacket, a heating chamber located outside ofthe water jacket, aplurality of electrical heating resistances located within said heating chamber for heating said water acket, a circuit for said resistances, a second circuit including a make-and-break device, a thermostat extending into said water jacket and adapted to automatically close the makeand-break circuit, the closin of said makeand-break c1rcu1t altering t e resistance 1n sald heating c1rcu1t, and an electric resistance in said make-and-break circuit adapted to be -automatically thrown into circuit with the first named resistances when the makeand-break circuit is closed by said thermostat.

3. In an incubator or bacteriological oven, the combination of a chamber having a water jacket, a heating chamber located outside of the water jacket, a plurality of heating resistances in said heating chamber normally in parallel, an electrical circuit for said resistances, a second electrical circuit including a make-and-break device, and a thermostat extending into said Water jacket and adapted to automatically close the make-and-break circuit, the closing of said last mentioned circuit throwing said resistances from parallel into series and thereby reducing their heating action.

4. In an incubator or bacteriological oven, the combination of a chamber having a water jacket, a heating chamber located outside of the water jacket, a normal heating resistance in said heating chamber, a regulating resistance also located in said heating chamber and which is normally inoperative, and a thermostatic device controlled by the temperature within the Water jacket for placing the regulating resistanceinto and out of circuit with the normal heating resist-ance.

In testimony whereof, I, the said HENRY LELAND LOWE, have hereunto set my hand.

HENRY L'ELAND LOWE.

Witnesses:

C. H. ABBE'rr, FRANK E. ABBETT. 

